The House and Senate adjourned for the year on Wednesday evening, closing a two-year term that holds the odd distinction of being both historically busy and epically unpopular.

A Congress that was dominated by Democrats passed more landmark legislation than any since the era of Lyndon B. Johnson's "Great Society."

Congress approved an $814 billion economic stimulus, a massive health-care overhaul, and new regulations on Wall Street trading and consumer credit cards. The list grew longer during this month's frenetic lame-duck session: tax cuts, a nuclear arms treaty and a repeal of the "don't ask, don't tell" policy on gays in the military.

But the 111th Congress will also be remembered for endless filibuster threats, volcanic town hall meetings, and the rise of the tea party. All were symbols of a dissatisfaction that peaked on Nov. 2, with a Republican rout in the midterm elections.

"This is the most dysfunctional political environment that I have ever seen. But then you have to juxtapose that with [this Congress being] one of, at least, the three most productive Congresses" since 1900, said Norman Ornstein, a scholar at the American Enterprise Institute.

"Making sense of all of that can make your head burst," he added.

The key to understanding this period, scholars say, is that the two parties were using radically different strategies.

Both thought they were playing the "long game" - the Republicans, by propelling themselves back into power; the Democrats, by writing their agenda into law.

On Wednesday, President Obama added another piece of that agenda into law, signing the repeal of "don't ask, don't tell." A few blocks away, Congress was using its last hours to approve two others: the New START nuclear arms pact with Russia, and a bill to extend health benefits to workers who responded to the Sept. 11, 2001, terrorist attacks.

The day had the feel of a victory lap, with Democrats rejuvenated only a few weeks after a historic electoral beating.

"This has been a season of progress for the American people," Obama said in a news conference. "This has been the most productive post-election period we've had in decades, and it comes on the heels of the most productive two years that we've had in generations."

Sen. Majority Leader Harry M. Reid (D-Nev.) was equally ebullient. "This was by far the most productive Congress in American history, and the lame-duck session we're finishing was the most productive of its kind," he said.